Greetings to the OP. Bet you didn't think you'd stir up all of this mess. With regard to your actual questions, ekpolk has done a good job in answering them.
Instant-on can be detected by any of the good detectors made these days (read any new product by Valentine, Beltronics, Escort, and a few models made by Whistler). You just have to make sure you dectect it hitting the cars in front of you and not you!
A radar detector is not a license to speed of course, and won't EVER provide complete protection. The serious contermeasure user will also employ laser protection where needed, but the newer jammers are pricey.
The Escort 9500ci, as one person mentioned, is the current king of the hill. But it is VERY pricey at around $1400-1500 per google. The dash version, the 9500ix, ranks comparable or close to the V1 in detection but has GPS lockout of falses plus a database of speed/stoplight cams.
Being owned by Escort, Beltronics has a very similar lineup. Many prefer the ramp-up of the 9500ci to the comparable Beltronics model, the STI-r. The dash mount version of the STI-r, though, is the only dash mount detector that is undetectable by police, though. So if you aim to use your detector in parts of Canada and Virginia, you will need either the STI-R, STI, or the 9500ci.
Other Escort/Beltronics products are all made off the same platform, as far as I know (m4). All that's going to vary is features. About the only thing to avoid is the RX-55, which is off an older, weaker and cheaper platform. Myself I have two slightly older S7 platform products, an Escort Passport 8500 and a Beltronics Vector 955. The Vector series is Beltronics bread and butter and you can't find anything better for the price. They use the same detection platform as the Escort Passport 8500 x50, and Beltronics RX-65. Not quite sure which platform the new GX-65 uses, though.
V1 is the detector of choice for the user that has to know every single radar emisiion for miles around. It, by default, doesn't filter anything and is VERY sensitive. It can be adjusted to raise it's alert threshold, but then you loose that V1 goodness.
Whistler makes three good detectors in a lineup that is otherwise pretty [censored]. The Pro78, XTR-690, and brand new XTR-695 are comparable to the Vectors from Beltronics.
Stay away from anything made by Cobra. It's not just that they provide poorer detection, it's that they provide spotty detection with no rhyme or reason.
As for mounting, if you haven't got any lidar to worry about, go as high as you can, as long as your tint strip doesn't have metallic paint. A radar detector is essentially a radio scanner with a highly directional horn antenna. So get it up high and pointed down the road for the best range. But really, as long as you don't have something obstructing the view out the windshield, it's not much of a difference.
Instant-on can be detected by any of the good detectors made these days (read any new product by Valentine, Beltronics, Escort, and a few models made by Whistler). You just have to make sure you dectect it hitting the cars in front of you and not you!
A radar detector is not a license to speed of course, and won't EVER provide complete protection. The serious contermeasure user will also employ laser protection where needed, but the newer jammers are pricey.
The Escort 9500ci, as one person mentioned, is the current king of the hill. But it is VERY pricey at around $1400-1500 per google. The dash version, the 9500ix, ranks comparable or close to the V1 in detection but has GPS lockout of falses plus a database of speed/stoplight cams.
Being owned by Escort, Beltronics has a very similar lineup. Many prefer the ramp-up of the 9500ci to the comparable Beltronics model, the STI-r. The dash mount version of the STI-r, though, is the only dash mount detector that is undetectable by police, though. So if you aim to use your detector in parts of Canada and Virginia, you will need either the STI-R, STI, or the 9500ci.
Other Escort/Beltronics products are all made off the same platform, as far as I know (m4). All that's going to vary is features. About the only thing to avoid is the RX-55, which is off an older, weaker and cheaper platform. Myself I have two slightly older S7 platform products, an Escort Passport 8500 and a Beltronics Vector 955. The Vector series is Beltronics bread and butter and you can't find anything better for the price. They use the same detection platform as the Escort Passport 8500 x50, and Beltronics RX-65. Not quite sure which platform the new GX-65 uses, though.
V1 is the detector of choice for the user that has to know every single radar emisiion for miles around. It, by default, doesn't filter anything and is VERY sensitive. It can be adjusted to raise it's alert threshold, but then you loose that V1 goodness.
Whistler makes three good detectors in a lineup that is otherwise pretty [censored]. The Pro78, XTR-690, and brand new XTR-695 are comparable to the Vectors from Beltronics.
Stay away from anything made by Cobra. It's not just that they provide poorer detection, it's that they provide spotty detection with no rhyme or reason.
As for mounting, if you haven't got any lidar to worry about, go as high as you can, as long as your tint strip doesn't have metallic paint. A radar detector is essentially a radio scanner with a highly directional horn antenna. So get it up high and pointed down the road for the best range. But really, as long as you don't have something obstructing the view out the windshield, it's not much of a difference.